“Old Man came from the south…”
Chewing Black Bones quoted by Ella Elizabeth Clark, Indian Legends from the Northern Rockies, originally published in 1967 by University of Oklahoma Press.

Further reading:

Cynthia Stokes Brown. Big History: From the Big Bang to the Present. New York: The New Press. 2007.

Bill Bryson. A Short History of Nearly Everything. New York: Broadway Books. 2003.

David Christian. Maps of Time: An Introduction to Big History. Berkeley: University of California Press. 2004.

Fred Spier. Big History and the Future of Humanity. Malden, MA. Blackwell Publishing. 2010.

Threshold 1

“Vos calculs sont corrects, mais votre physique est abominable”
Albert Einstein quoted by André Deprit, “Monsignor Georges Lemaître,” in The Big Bang and Georges Lemaître: Proceedings of a Symposium in Honour of G. Lemaître Fifty Years After His Initiation of Big-Bang Cosmology, edited by A. Berger, originally published in 1983 by D. Reidel.  

I am an observer, not a theoretical man” 
Edwin Hubble quoted by Tom Bezzi, Hubble Time, originally published in 1987 by Mercury House. An account of Hubble’s life and achievements as told by his fictional granddaughter, based on diaries written by and interviews with Hubble’s actual widow, Grace. 

“If the world has begun with a single quantum…”
Georges Lemaître, “The Beginning of the World from the Point of View of Quantum Theory,” letter, Nature 127 (May 9, 1931). 

Further reading:

Marcia Bartusiak. The Day We Found the Universe. New York: Random House. 2009.

Simon Singh. Big Bang: The Origin of the Universe. New York: Harper Collins. 2004.

Threshold 2

Further reading:

Edward Dolnick. The Clockwork Universe: Isaac Newton, the Royal Society, and the Birth of the Modern World. New York: Harper Collins. 2011.

Threshold 3

“Finally we shall place the Sun himself at the center of the Universe”
Copernicus, On the Revolutions of the Heavenly Spheres, printed in Nuremberg in 1543; cited in Thomas S. Kuhn, The Copernican Revolution: Planetary Astronomy in the Development of Western Thought, originally published in 1957 by Harvard University Press. 

Further reading:

Sam Kean. The Disappearing Spoon. New York: Little, Brown and Company. 2010.

Threshold 4

“We [scientists] are like a judge…”
Alfred Wegener, The Origin of Continents and Oceans, originally published in 1915 by Braunschweig, F. Vieweg; translation by John Biram, originally published in 1966 by Dover. 

“Wegener’s hypothesis in general is of the footloose type”
Rollin T. Chamberlin quoted by University of California Museum of Paleontology (UCMP), “Alfred Wegener (1880-1930),”

Special thanks to the Alfred Wegener Institute for Polar and Marine Research. (

Further reading:

Roger M. McCoy. Ending in Ice: The Revolutionary Idea and Tragic Expedition of Alfred Wegener. New York: Oxford University Press. 2006.

Threshold 5

“Something is wrong”
Frank Asaro quoted by Walter Alvarez, “How We Proved an Asteroid Wiped Out the Dinosaurs,” video, recorded for the Big History Project at UC Berkeley, 2011.

“The problem then was, not only how and why do species change…”
“And the answer was clearly, that on the whole– the best fitted live…”
Alfred Russel Wallace, My Life: A Record of Events and Opinions, originally published in 1905 by Dodd, Mead and Company. 

Multiply, vary, let the strongest live and the weakest die.
Charles Darwin, On the Origin of Species by Means of Natural Selection, originally published in 1859 by John Murray.

Select Charles Darwin images reproduced with permission from John van Wyhe ed. The Complete Work of Charles Darwin Online. (

Further reading:

Walter Alvarez. T. rex and the Crater of Doom. Princeton, NJ: Princeton University Press. 1997.

Ross A. Slotten. The Heretic in Darwin’s Court: The Life of Alfred Russel Wallace. New York: Columbia University Press. 2004.

Threshold 6

“It takes a great deal of patience to make an arrow…”
Village elder, conversation with writer Peter Stark and his son, Yanomami village, Amazonas, Brazil, January 29, 2011. 

Further reading:

Gerard Helferich. Humboldt’s Cosmos: Alexander von Humboldt and the Latin American Journey that Changed the Way We See the World. New York: Gotham. 2004.

Davi Kopenawa and Bruce Albert. The Falling Sky: Words of a Yanomami Shaman. Cambridge, MA: Harvard University Press. 2013.

Threshold 7

“I have collected grain for the people…”
“From a distant journey [Gilgamesh] came home…”
“Eat the bread, Enkidu…”
Modified from Benjamin R. Foster, translator and editor, The Epic of Gilgamesh, published in 2001 by W.W. Norton & Co.

“Agriculture allows a small number of people to feed a multitude of people…”
Evan Fraser, interview with Peter Stark, July 2013.

Further reading:

Evan Fraser and Andrew Rimas, Empires of Food: Feast, Famine, and the Rise and Fall of Civilizations. New York: Free Press. 2010.

Threshold 8

“If the presence of electricity can be made visible…”
Samuel F.B. Morse, His Letters and Journals, edited and supplemented by his son, Edward Lind Morse, originally published in 1914 by Houghton Mifflin. 

“It is a triumph more glorious, because far more useful to mankind…”
James Buchanan quoted in J.A. Spencer, History of the United States, From the Earliest Period to the Administration of President Johnson, originally published in 1866 by Johnson, Fry and Company.

Further reading:

David B. Abernathy. The Dynamics of Global Dominance. New Haven, CT: Yale University Press. 2000.

Jared Diamond. Guns, Germs, and Steel: The Fates of Human Societies. New York: W.W. Norton & Co., 1999.


“We sat down on the very edge of the wall…”
John Lloyd Stephens, Incidents of Travel in Central America, Chiapas and Yucatan, originally published in 1841 by Harper and Brothers.

“Change is the process by which the future invades our lives”
Alvin Toffler, Future Shock, originally published in 1970 by Random House.

Further reading:

Joseph Tainter. The Collapse of Complex Societies. New York & Cambridge, UK: Cambridge University Press. 1988.